In mobile devices such as mobile telephones and notebook computers for which mobility is important, the sizes of the input operation parts such as keys and pointing devices used for typing email messages, or inputting telephone numbers or scrolling while playing games are generally kept to a minimum. When a user enters data into a mobile device while using a transit system accompanied by fluctuations, such as train and bus, an abrupt shock might cause the pointing device to miss the intended target area or the user to press the wrong keys, forcing the user to re-enter the data. It is possible to prevent such erroneous operations by enlarging the idle part of the pointing device or widening the key intervals.
[Patent Document 1]    Japanese Patent Kokai Publication No. JP-P2000-100272A
[Patent Document 2]    Japanese Patent Kokai Publication No. JP-A-4-113780
[Patent Document 3]    Japanese Patent Kokai Publication No. JP-A-7-288726
[Patent Document 4]    Japanese Patent Kokai Publication No. JP-A-7-245043
[Patent Document 5]    Japanese Patent Kokai Publication No. JP-P2002-82766A
[Patent Document 6]    Japanese Patent Kokai Publication No. JP-P2003-335192A